Issue 3143 - Filter elements with :-abp-has()

chrome/content/elemHideEmulation.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /* globals filterToRegExp */
 
 "use strict";
 
-let propertySelectorRegExp = /\[-abp-properties=(["'])([^"']+)\1\]/;
-
 function splitSelector(selector)
 {
   if (selector.indexOf(",") == -1)
     return [selector];
 
   let selectors = [];
   let start = 0;
   let level = 0;
   let sep = "";
 
@@ skipping 18 matching lines @@
         selectors.push(selector.substring(start, i));
         start = i + 1;
       }
     }
   }
 
   selectors.push(selector.substring(start));
   return selectors;
 }
 
+/** Return position of node from parent.
+ * @param {Node} node - the node to find the position of.
+ * @return {number} 1 base index like for :nth-child(), or 0 on error.
+ */
+function positionInParent(node)
+{
+  if (!node)
+    return 0;
+  let {children} = node.parentNode;
+  for (let i = 0; i < children.length; i++)
+    if (children[i] == node)
+      return i + 1;
+  return 0;
+}
+
+function makeSelector(node, selector)
+{
+  if (!node.parentElement)
+  {
+    let newSelector = ":root";
+    if (selector)
+      newSelector += " > ";
+    return newSelector + selector;
+  }
+  let idx = positionInParent(node);
+  if (idx > 0)
+  {
+    let newSelector = `${node.tagName}:nth-child(${idx})`;
+    if (selector)
+      newSelector += " > ";
+    return makeSelector(node.parentElement, newSelector + selector);
+  }
+
+  return selector;
+}
+
+const abpSelectorRegexp = /:-abp-(properties|has|[A-Za-z\d-]*)\(/i;
+
+function parseSelectorContent(content, quoted = false)
+{
+  let parens = 1;
+  let i = 0;
+  let quote = null;
+  let originalLength = content.length;
+  if (quoted)
+    content = content.trim();
+  while (i < content.length)
+  {
+    let c = content[i];
+    if (quoted && i == 0)
+    {
+      if (c != "'" && c != '"')
+        return null;
+    }
+    if (c == "\\")
+      i++;
+    else if (quote)
+    {
+      if (c == quote)
+        quote = null;
+    }
+    else if (c == "'" || c == '"')
+    {
+      quote = c;
+    }
+    else if (c == "(")
+      parens++;
+    else if (c == ")")
+    {
+      parens--;
+      if (parens == 0)
+        break;
+    }
+    i++;
+  }
+  if (parens > 0)
+    return null;
+  if (quoted)
+  {
+    let end = content.substr(0, i).lastIndexOf(content[0]);
+    return {text: content.substr(1, end - 1),
+      end: i + (originalLength - content.length)};
+  }
+  return {text: content.substr(0, i), end: i};
+}
+
+function parseSelector(selector, level = 0)
+{
+  if (selector.length == 0)
+    return [];
+
+  let match = abpSelectorRegexp.exec(selector);
+  if (!match)
+    return [new PlainSelector(selector)];
+
+  let selectors = [];
+  let suffixStart = match.index;
+  if (suffixStart > 0)
+    selectors.push(new PlainSelector(selector.substr(0, suffixStart)));
+
+  let startIndex = match.index + match[0].length;
+  let content = null;
+  if (match[1] == "properties")
+  {
+    content = parseSelectorContent(selector.substr(startIndex), true);
+    if (content == null)
+    {
+      console.error(new SyntaxError("Failed to parse AdBlock Plus " +
+                                    `selector ${selector}, invalid ` +
+                                    "properties string."));
+      return null;
+    }
+
+    selectors.push(new PropsSelector(content.text));
+  }
+  else if (match[1] == "has")
+  {
+    if (level > 0)
+    {
+      console.error(new SyntaxError("Failed to parse AdBlock Plus " +
+                                    `selector ${selector}, invalid ` +
+                                    "nested :-abp-has()."));
+      return null;
+    }
+
+    content = parseSelectorContent(selector.substr(startIndex));
+    if (content == null)
+    {
+      console.error(new SyntaxError("Failed parsing AdBlock Plus " +
+                                    `selector ${selector}, didn't ` +
+                                    "find closing parenthesis."));
+      return null;
+    }
+
+    let hasSelector = new HasSelector(content.text);
+    if (!hasSelector.valid())
+      return null;
+    selectors.push(hasSelector);
+  }
+  else
+  {
+    // this is an error, can't parse selector.
+    console.error(new SyntaxError("Failed parsing AdBlock Plus " +
+                                  `selector ${selector}, invalid ` +
+                                  `pseudo-class -abp-${match[1]}.`));
+    return null;
+  }
+
+  suffixStart = startIndex + content.end + 1;
+
+  let suffix = parseSelector(selector.substr(suffixStart), level);
+  if (suffix == null)
+    return null;
+
+  selectors.push(...suffix);
+
+  return selectors;
+}
+
+function *findPropsSelectors(styles, prefix, regexp)
+{
+  for (let style of styles)
+    if (regexp.test(style.style))
+      for (let subSelector of style.subSelectors)
+        yield prefix + subSelector;
+}
+
+function stringifyStyle(style)
+{
+  let styles = [];
+  for (let i = 0; i < style.length; i++)
+  {
+    let property = style.item(i);
+    let value = style.getPropertyValue(property);
+    let priority = style.getPropertyPriority(property);
+    styles.push(property + ": " + value + (priority ? " !" + priority : "") +
+                ";");
+  }
+  styles.sort();
+  return styles.join(" ");
+}
+
+function* evaluate(chain, index, prefix, subtree, styles)
+{
+  if (index >= chain.length)
+  {
+    yield prefix;
+    return;
+  }
+  for (let [selector, element] of
+       chain[index].getSelectors(prefix, subtree, styles))
+    yield* evaluate(chain, index + 1, selector, element, styles);
+}
+
+function PlainSelector(selector)
+{
+  this._selector = selector;
+}
+
+PlainSelector.prototype = {
+  /**
+   * Generator function returning a pair of selector
+   * string and subtree.
+   * @param {String} prefix - the prefix for the selector.
+   * @param {Node} subtree - the subtree we work on.
+   * @param {Array} styles - the stringified stylesheets.
+   */
+  *getSelectors(prefix, subtree, styles)
+  {
+    yield [prefix + this._selector, subtree];
+  },
+
+  /**
+   * Generator function returning selected elements.
+   * @param {String} prefix - the prefix for the selector.
+   * @param {Node} subtree - the subtree we work on.
+   * @param {Array} styles - the stringified stylesheets.
+   */
+  *getElements(prefix, subtree, styles)
+  {
+    for (let [selector] of this.getSelectors(prefix, subtree, styles))
+      for (let element of subtree.querySelectorAll(selector))
+        yield element;
+  }
+};
+
+const prefixEndRegexp = /[\s>+~]$/;
+
+function HasSelector(selector, level = 0)
+{
+  this._innerSelectors = parseSelector(selector, level + 1);
+}
+
+HasSelector.prototype = {
+  valid()
+  {
+    return this._innerSelectors != null;
+  },
+
+  *getSelectors(prefix, subtree, styles)
+  {
+    for (let element of this.getElements(prefix, subtree, styles))
+      yield [makeSelector(element, ""), element];
+  },
+
+  *getElements(prefix, subtree, styles)
+  {
+    let actualPrefix = (!prefix || prefixEndRegexp.test(prefix)) ?
+        prefix + "*" : prefix;
+    let elements = subtree.querySelectorAll(actualPrefix);
+    for (let element of elements)
+    {
+      let newPrefix = makeSelector(element, "");
+      let iter = evaluate(this._innerSelectors, 0, "", element, styles);
+      for (let selector of iter)
+        // we insert a space between the two. It becomes a no-op if selector
+        // doesn't have a combinator
+        if (subtree.querySelector(newPrefix + " " + selector))
+          yield element;
+    }
+  }
+};
+
+function PropsSelector(propertyExpression)
+{
+  let regexpString;
+  if (propertyExpression.length >= 2 && propertyExpression[0] == "/" &&
+      propertyExpression[propertyExpression.length - 1] == "/")
+  {
+    regexpString = propertyExpression.slice(1, -1)
+      .replace("\\x7B ", "{").replace("\\x7D ", "}");
+  }
+  else
+    regexpString = filterToRegExp(propertyExpression);
+
+  this._regexp = new RegExp(regexpString, "i");
+}
+
+PropsSelector.prototype = {
+  *getSelectors(prefix, subtree, styles)
+  {
+    for (let selector of findPropsSelectors(styles, prefix, this._regexp))
+      yield [selector, subtree];
+  },
+
+  *getElements(prefix, subtree, styles)
+  {
+    for (let [selector] of this.getSelectors(prefix, subtree, styles))
+      for (let subElement of subtree.querySelectorAll(selector))
+        yield subElement;
+  }
+};
+
 function ElemHideEmulation(window, getFiltersFunc, addSelectorsFunc)
 {
   this.window = window;
   this.getFiltersFunc = getFiltersFunc;
   this.addSelectorsFunc = addSelectorsFunc;
 }
 
 ElemHideEmulation.prototype = {
-  stringifyStyle(style)
-  {
-    let styles = [];
-    for (let i = 0; i < style.length; i++)
-    {
-      let property = style.item(i);
-      let value = style.getPropertyValue(property);
-      let priority = style.getPropertyPriority(property);
-      styles.push(property + ": " + value + (priority ? " !" + priority : "") +
-                  ";");
-    }
-    styles.sort();
-    return styles.join(" ");
-  },
-
   isSameOrigin(stylesheet)
   {
     try
     {
       return new URL(stylesheet.href).origin == this.window.location.origin;
     }
     catch (e)
     {
       // Invalid URL, assume that it is first-party.
       return true;
     }
   },
 
-  findSelectors(stylesheet, selectors, filters)
-  {
-    // Explicitly ignore third-party stylesheets to ensure consistent behavior
-    // between Firefox and Chrome.
-    if (!this.isSameOrigin(stylesheet))
-      return;
-
-    let rules = stylesheet.cssRules;
-    if (!rules)
-      return;
-
-    for (let rule of rules)
-    {
-      if (rule.type != rule.STYLE_RULE)
-        continue;
-
-      let style = this.stringifyStyle(rule.style);
-      for (let pattern of this.patterns)
-      {
-        if (pattern.regexp.test(style))
-        {
-          let subSelectors = splitSelector(rule.selectorText);
-          for (let subSelector of subSelectors)
-          {
-            selectors.push(pattern.prefix + subSelector + pattern.suffix);
-            filters.push(pattern.text);
-          }
-        }
-      }
-    }
-  },
-
   addSelectors(stylesheets)
   {
     let selectors = [];
     let filters = [];
+
+    let cssStyles = [];
+
     for (let stylesheet of stylesheets)
-      this.findSelectors(stylesheet, selectors, filters);
+    {
+      // Explicitly ignore third-party stylesheets to ensure consistent behavior
+      // between Firefox and Chrome.
+      if (!this.isSameOrigin(stylesheet))
+        continue;
+
+      let rules = stylesheet.cssRules;
+      if (!rules)
+        continue;
+
+      for (let rule of rules)
+      {
+        if (rule.type != rule.STYLE_RULE)
+          continue;
+
+        let style = stringifyStyle(rule.style);
+        let subSelectors = splitSelector(rule.selectorText);
+        cssStyles.push({style, subSelectors});
+      }
+    }
+
+    for (let patterns of this.selPatterns)
+      for (let selector of evaluate(patterns.selectors,
+                                    0, "", document, cssStyles))
+      {
+        selectors.push(selector);
+        filters.push(patterns.text);
+      }
+
     this.addSelectorsFunc(selectors, filters);
   },
 
   onLoad(event)
   {
     let stylesheet = event.target.sheet;
     if (stylesheet)
       this.addSelectors([stylesheet]);
   },
 
   apply()
   {
     this.getFiltersFunc(patterns =>
     {
-      this.patterns = [];
+      this.selPatterns = [];
+
       for (let pattern of patterns)
       {
-        let match = propertySelectorRegExp.exec(pattern.selector);
-        if (!match)
-          continue;
-
-        let propertyExpression = match[2];
-        let regexpString;
-        if (propertyExpression.length >= 2 && propertyExpression[0] == "/" &&
-            propertyExpression[propertyExpression.length - 1] == "/")
-        {
-          regexpString = propertyExpression.slice(1, -1)
-              .replace("\\x7B ", "{").replace("\\x7D ", "}");
-        }
-        else
-          regexpString = filterToRegExp(propertyExpression);
-
-        this.patterns.push({
-          text: pattern.text,
-          regexp: new RegExp(regexpString, "i"),
-          prefix: pattern.selector.substr(0, match.index),
-          suffix: pattern.selector.substr(match.index + match[0].length)
-        });
-      }
-
-      if (this.patterns.length > 0)
+        let selectors = parseSelector(pattern.selector);
+        if (selectors != null && selectors.length > 0)
+          this.selPatterns.push({selectors, text: pattern.text});
+      }
+
+      if (this.selPatterns.length > 0)
       {
         let {document} = this.window;
         this.addSelectors(document.styleSheets);
         document.addEventListener("load", this.onLoad.bind(this), true);
       }
     });
   }
 };